简并费米气体与微腔相互作用的非平衡多体效应及调控

Exploring nonequilibrium many-body effects is a key and interdisciplinary research project among quantum physics, statistical physics, atomic and molecular physics, and condensed-matter physics. To deeply investigate it not only has important significance in fundamental science, but also puts forward a new method of quantum manipulation and quantum technique. Based on current experimental development and the applicant’s previous achievement, our project is devoted to studying the dissipation-induced nonequilibrium superfluids for two-dimensional degenerate Fermi gases. The specific consideration is divided into three parts as follows. The first is to investigate the nonequilibrium BCS-BEC crossover, FFLO superfluid, and BKT transition, especially to reveal the nontrivial critical behaviors at the points when the nonequilibrium phase transitions occur. The second is to predict exotic equilibrium and nonequilibrium quantum states induced by the compound long- and short-range interactions between fermions. The last is to establish topological quantum field for open systems, and then to predict the nonequilibrium topological superfluids. During the time of the project, about ten papers are expected to be published in Physcial Review or other journals, whose impact factors are beyond 3.0.

探索非平衡多体效应是量子物理、统计物理、原子分子物理和凝聚态物理等多个学科交叉的一个关键课题。通过对该课题的深入研究不仅具有重要的基础科学意义，而且能为量子调控和量子技术提供新的手段。根据当前实验方面的发展和申请人已取得的前期成果，本申请项目将主要研究在二维简并费米气体中光子耗散诱导的非平衡超流问题。具体分为：(1) 揭示非平衡的BCS-BEC渡越、FFLO超流和BKT转变，并获得非平衡相变点的奇异临界行为；(2) 调控费米原子间的长程和短程复合相互作用，预言新的平衡或非平衡物态；(3) 建立开放系统的拓扑量子场论，预言奇异的非平衡拓扑超流。预期在《Physical Review》系列或者影响因子大于3.0的刊物上发表10篇左右的学术论文。

探索非平衡多体效应是量子物理、统计物理、原子分子物理和凝聚态物理等多个学科交叉的一个关键课题。通过对该课题的深入研究不仅具有重要的基础科学意义，而且能为量子调控和量子技术提供新的手段。本项目主要研究超冷原子与微腔相互作用体系的非平衡多体效应及调控，尤其在新奇物态的预言、操控及应用方面取得了系列成果。譬如，率先在实验上证实高阶拓扑半金属；通过密度矩阵重整化群数值计算方法和对称群的投影表象理论，发现了具有费米边缘态及Z4拓扑不变量的新对称性保护拓扑态；建立SU（3）的量子磁性理论，发现了量子螺旋张量态和拓扑顺磁态；在Fock态基矢下建立了Keldysh-Heisenberg非平衡量子场论，解决了少光子情况下的量子涨落问题；利用短程相互作用与腔诱导的长程相互作用之间的竞争，预言了具有自旋密度波序的超固态；设计腔场诱导的振动光晶格实现了丰富的长程跃迁项，发现了高绕数的拓扑超辐射态；通过控制腔中原子之间的耦合，实现了拓扑保护的量子态长程转移。.项目执行期间负责人作为通讯作者共发表SCI收录论文21篇，其中《Nature Materials》1篇、《Physical Review Letters》1篇、《Physical Review A/B》17篇、《SCIENCE CHINA: Physics, Mechanics & Astronomy》1篇、《Scientific Reports》1篇。作为合作者在《Optics Letters》上发表论文1篇。